Hopes of alien life on Mars were dashed Thursday when a paper published in the journal Science concluded that the Curiosity rover has yet to find any methane gas, a strong indicator of microbial life. But Robert Zubrin, cofounder and president of the Mars Society, says that the search for alien life on Mars is only just beginning.

The Mars Society, founded in 1998, is the world's largest space advocacy non-profit organization, with chapters in the US, Canada and nearly every major European country. Zubrin, who's background in science includes a Ph.D in nuclear engineering and masters degrees in both aeronautics and astronautics, is outspoken about the stagnancy of NASA and the efforts of the US's various spaceflight missions.

"I don't think people want to have a human spaceflight program that just goes up and down from the International Space Station," Zubrin says.

In a phone interview Friday, Zubrin further outlined what the recent NASA findings mean for the future of finding life on the red planet. He also expounded on what the necessary steps forward are in keeping public interest in the origin of life alive while expanding the goals and focus of the various government-funded and private spaceflight companies.

Q: What's do you think will be the biggest impact of these findings, and where does the pursuit for finding life on Mars now stand?
Zubrin: We did not get the home run we had hoped for in finding methane. That was a disappointment. That does not mean that there is no methane on Mars. Just that there is no methane where Curiosity is.

If it had discovered methane it would have proven that there is life on Mars or hydrothermal environments on Mars that host microbial life. But I don't think we will likely find it on the surface. I think we'll find it in ground water.

Mars was warm and wet on its surface during its first billion years and then it became cold and dry and not hospitable to life. I think any Martian organisms who lived on the surface at that time have retreated underground.

So I think to find it we're going to have to go any drill. That will require human explorers.

What will life on Mars look like and what questions will arise when we find it?
Zubrin: If we do drill for life on Mars and find it and analyze it, there's a couple things we could find.

Are they just like Earth organisms? And then there's a chance of transfer of life from Earth to Mars with meteorites, or their [Mars'] ancestors being transferred here.

"If all life on Mars was like PCs and we went to Mars and found a Mac ... that would be very interesting."

That could be resolved if we find organisms on Mars that are more primitive in their development than terrestrial bacteria. If we can find organisms on Mars that included things like bacteria but also things more primitive and that would suggest life started on Mars and came to Earth. Because thinking of bacteria as the first organism is like thinking the first machine was an iPhone.

Then finally, if we found life in the ground water that was different than life on Earth. If all life on Mars was like PCs and we went to Mars and found a Mac ... that would be very interesting. That you actually can have two separate genesis events in one solar system.

We know that planets are highly probable, and that would mean that life is everywhere.

When do you think we'll see humans on Mars and what are the obstacles?
Zubrin: NASA has the technical abilities, and the US has the money. We could send a human to mars in 10 years. From a technical point of view, we are more capable of sending humans to Mars [now] than we were sending a man to the moon in 1961.

But NASA doesn't have a goal. This is a serious problem. A NASA without a goal may easily find itself cut to pieces because it's difficult to ask for money when it's not clear why you're asking for it.

NASA better get its head together and propose a plan. I don't think people want to have a human spaceflight program that just goes up and down from the International Space Station.

Elon Musk wants to get to Mars. He's got a fortune and a rocket company. The question is whether he'd really want to spend all his own money to send a human mission there. I think if it's a NASA mission to send humans to Mars, he could make it more affordable.

Then you have private groups like Mars One who don't have the resources. They have a bolder plan which is one-way mission. That's a settlement mission, not a suicide mission.

And the money is out there. It's out there in all these billionaires running around and out there frankly in the space-interested public. So in principal it's possible, but it's a question of putting it together.

What is left for the Curiosity rover now that one of its principal purposes -- finding evidence of life through methane detection -- has not succeeded?

Zubrin: Curiosity rover can do all kinds of things. It could find fossils. It has imaging capability, a telescope for microorganisms. Maybe a puff of methane will come and it will be detected later. There's lot for Curiosity to look for.

If you did discover methane, you might be able to resolve that with correct instruments. Curiosity might be able to resolve that.

And even if you said there was life, was it life transfer from Earth to Mars back when Mars had oceans? Or is it that there are pre-bacteria on Mars. It could fill some missing links: how did life actually evolve?

Alternatively, it could be a second genesis. We wouldn't know the answer. We would need to look at the organisms. We have to send people.